Michael Phelps, who won six medals in London to become the most decorated Olympian ever, swore he would never swim again. Less than a year later, there were whispers. He faced comeback speculation while attending the 2013 World Championships as a spectator, even from FINA’s president.

Finally, on Oct. 18, the reports started coming: Phelps was training again. He re-entered the U.S. Anti-Doping Agency drug-testing pool, clearing the way for a return to the sport. He raced for the first time in 20 months at a meet in April and has competed every month since, getting closer to that 2012 form.

Phelps is entered in four individual events at this week’s U.S. Championships in Irvine, Calif. He has not committed to competing through the Rio Olympics, and it appears he won’t swim as many events as he did in 2004 (eight), 2008 (eight) or 2012 (seven).

Ryan Lochte entered London 2012 as the world’s best swimmer but won fewer medals than Phelps at the Games. With Phelps’ retirement, Lochte had the mantle to himself again.

Lochte came back too early, missed more meets and returned in July and was beaten by Phelps in all three of their races. He arguably has more to prove than Phelps going forward, beginning with the U.S. Championships this week.

Missy Franklin‘s rise continued after she won five medals (four gold) as a 17-year-old at London 2012. In 2013, Franklin finished high school and then became the first woman to win six gold medals at a single World Championships.

This year, Franklin won an NCAA title at California and is again among the fastest freestylers and backstrokers in the U.S., despite a late start to the Grand Prix season due to classes.

KatieLedecky, a rising high school senior,has been the most impressive swimmer this year, two years after winning Olympic 800m free gold at age 15. She was arguably more impressive than Franklin last year, too, winning the female World Swimmer of the Year, USOC Sportswoman of the Year and USA Swimming’s female Athlete of the Year.

A Stanford commit, Ledecky broke two distance freestyle world records in June. She’s lining up to potentially swim four events in Rio, including, perhaps, a 200m free showdown with Franklin. U.S. women’s swimmers haven’t gone one-two at an Olympics or World Championships since 2000.

Around the world, China’s mercurial Sun Yang remains the dominant distance force. JamesMagnussen, the poster boy for Australia’s 2012 Olympic shortcomings,has rebounded to lead a resurgent contingent. Many eyes in Rio de Janeiro are on Cesar Cielo, the 2008 Olympic and 2013 World champion in the 50m free.

The world’s best female all-around swimmer is Hungary’s Katinka Hosszu, the reigning World champion in both individual medleys. The U.S. women beat Australia in all three relays at 2013 Worlds, but the Aussies just broke the 4x100m world record, led by superstar Cate Campbell.

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Russian Yevgenia Medvedeva broke the record for highest women’s short program score at the Grand Prix Final on Friday.

Medvedeva, who hasn’t lost in more than one year, totaled 79.21 points in Marseille, France. That beat Mao Asada‘s 78.66 from the 2014 World Championships, the previous record under a decade-old judging system.

“I knew approximately about the record,” Medvedeva said through a translator. “For me, it’s one step further.”

Medvedeva leads Canadian Kaetlyn Osmond by 3.67 points going into Saturday’s free skate. No U.S. woman qualified for the six-skater Grand Prix Final for the first time since 2008.

She already holds the free skate world record and can break Yuna Kim‘s record for total score with a solid effort Saturday in Marseille. Medvedeva said she can perform better than she did Friday, specifically with her program interpretation and spins.

“I always strive for perfection,” she said through a translator. “When you stop doing that, you will stop progress.”

The Grand Prix Final concludes with the women’s and men’s free skates and free dance Saturday (schedule here). NBCSN will air coverage Sunday from 8:30-11 p.m. ET.

Earlier Friday, Russians Yevgenia Tarasova and Vladimir Morozov held onto their short-program lead to win the pairs event by 7.14 points over China’s Yu Xiaoyu and Zhang Hao.

Canadians Meagan Duhamel and Eric Radford, the two-time world champions and pre-event favorites, struggled in the short program and free skate and lost for just the second time in the last three seasons.

In the short dance, Canadians Tessa Virtue and Scott Moir recorded the highest score of all time, an 80.50, to take a 2.53-point lead into Saturday’s free dance.

That Virtue and Moir lead is no surprise — they were the top couple in the fall Grand Prix season — but their closest challenger is a surprise.

It is not two-time world champions Gabriella Papadakis and Guillaume Cizeron of France, but instead Americans Maia and Alex Shibutani, who totaled a personal-best short dance.

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Gracie Gold struggled in all four of her competitions this fall, capped by her lowest total score in four years at a Croatian event this week, putting her under scrutiny for the U.S. Championships in six weeks.

She singled three jumps and fell twice across two programs at Golden Spin in Zagreb, Croatia, on Thursday and Friday.

Gold totaled 159.02 points for sixth place, her first time below 160 points since 2012 Skate Canada in her first season as a senior skater.

Italian Carolina Kostner, the 2014 Olympic bronze medalist, won with 196.23 points in her first full competition since the 2014 World Championships.

Earlier this fall, Gold finished last of six skaters in the free skate-only Japan Open on Oct. 1, fifth at Skate America in October and eighth at Trophée de France in November.

Gold has spoken openly about trying to mentally and physically recover from last season’s world championships, where she dropped from first after the short program to finish fourth, and taking weeks off from training in the summer offseason.

Even with the rough skates, Gold still ranks fourth among U.S. women in top scores this season, behind Ashley Wagner, Mariah Bell and Mirai Nagasu.

She could struggle — to a degree — at the U.S. Championships in January and still make the three-woman world championships team. Gold has finished first or second at all four of her senior nationals appearances.